Probing the Mechanism of Anion Exchange in Cesium Lead Halide
Perovskites via gas cell TEM
EMSL Project ID
60262
Abstract
My proposed research project seeks to elucidate the anion exchange mechanism of CsPbX3 perovskites and related materials using the advanced electron microscopy resources available at PNNL. Colloidal CsPbX3 (X = Cl, Br, I) perovskite nanocrystals have attracted a great deal of interest due to their bright, narrow emission, high photoluminescence quantum yields, tunable band gap, and defect tolerance. A characteristic property of CsPbX3 nanocrystals is their facile anion-exchange chemistry in the liquid or gas phase, which allows ready conversion between different halide structures, formation of mixed halide compositions, and access to materials that are difficult or impossible to synthesize directly. The mechanism(s) by which this anion exchange occurs are still poorly understood. My thesis work focuses on probing these reactions at the atomistic level to gain mechanistic insight into this important chemical transformation. As part of my studies, I propose to use ETEM and HRSTEM to study this exchange at multiple points ex-situ and in-situ in the gas phase. Furthermore, the anion exchange reaction is thermally driven, and can be halted by plunging into liquid nitrogen. The Cryo-TEM resources at PNNL can then be employed to observe crystal structure and lattice parameters mid-exchange. The proposed work at PNNL will employ these high-resolution and in-situ techniques available at EMSL and PSL to probe the anion exchange behavior in halide perovskite nanomaterials.
Project Details
Start Date
2021-11-09
End Date
2022-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members